[Role of sialo compounds in choline uptake by synaptosomes].
Two kinetic mechanisms are responsible for the uptake of choline in Rat brain synaptosomal fractions with different affinity towards the substrate (high affinity mechanism: Km 5.1 microM, Vmax 44 pmol/mg prot/min.; low affinity mechanism: 35.7 microM, Vmax 286 pmol/mg prot/min). The treatment of synaptosomal fractions with neuraminidase (15 min. at 37 degrees C) followed by 1 min. incubation with various concentrations of [14C] choline reduces the uptake in parallel with the disappearance of the high affinity mechanism (Km 202.2 microM, Vmax 119 pmol/mg prot/min.), without influencing the synthesis of acetylcholine.
D000109:Acetylcholine / Q000096:biosynthesis; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D002794:Choline / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D009439:Neuraminidase / Q000494:pharmacology*; D051381:Rats; D013574:Synaptosomes / Q000378:metabolism*
D009439:Neuraminidase; D002794:Choline; D000109:Acetylcholine
Rôle des sialocomposés dans la capture de la choline dans les synaptosomes.